No, not concerned at all. If very fresh hatching eggs they'd not have an air cell started at all. My cells usually are tiny day 7 but catch up to standard model size by day 14. Eggs need to lose moisture through the incubation period, the loss of water results in open air cell at fat end of egg. It this air pocket that the chicks head moves into when they turn around in the egg prior to piping and zipping the shell. The air cell needs to be large enough for the chicks to breath. It's that simple. The lower RH you incubate at the faster the air cell grows and in reverse the higher the RH the slower or no growth occurs. 25-35% RH is a good place to be during first 18 days then you up it to 70% + RH for last few days when they hatch.
Here's a diagram that's all over these BYC pages. It's not meant to be exacting rather a good model to stay in range of. If your cells are as large or larger than what is indicated for day 14 on day 18 you'll be fine. If they are huge day 14 up humidity early to stop growth. It's a good monitoring system when candling day 14 and gives you time to make adjustment if needed:
Photo above is how you can preform a salt test: Saturated salt at all normal home temp and incubation temp range is 75% RH +/- 1%. A calibration is nothing more than creating a salt environment and taking a reading with your hygrometer. How far it's off from 75 is your calibration. You always add or subtract the difference from your units reading to know true RH.
In a nutshell here's how I do a salt test:
Milk cap or any small cap/container filled with salt; add drops of water until saturated. I pour off any standing water.
Put cap and hygrometer into a sealed container. I use quart sized zip seal bags and allow for small pillow of air. Voila! A saturated salt environment.
Wait...then wait some more...I calibrated yesterday and after 6 hours the RH reading was finally steady as it didn't change hour 7 and called it.
Subtract your reading from 75 and write that number down on masking tape and stick it to your incubator as reminder.
Ex: your reading is 85%, 75-85= -10, you'll always subtract 10 from your units reading for true RH. My unit yesterday was 8% off and have read of peoples devices being off as much as 15%. It makes a big difference if your 15% low at hatch time (chicks will dry and stick to shell and unable to zip) or can't figure out why the air cells are not growing or growing too large.
Note: battery powered hygrometers will vary a lot depending how new or drained the battery is. Always perform a salt test start of every hatch season and if the battery is changed.
For instance by unit last year was off 2% and with same battery in was off 8% yesterday and today the battery died so am performing a new test as it has a new battery.
Here's a diagram that's all over these BYC pages. It's not meant to be exacting rather a good model to stay in range of. If your cells are as large or larger than what is indicated for day 14 on day 18 you'll be fine. If they are huge day 14 up humidity early to stop growth. It's a good monitoring system when candling day 14 and gives you time to make adjustment if needed:
Photo above is how you can preform a salt test: Saturated salt at all normal home temp and incubation temp range is 75% RH +/- 1%. A calibration is nothing more than creating a salt environment and taking a reading with your hygrometer. How far it's off from 75 is your calibration. You always add or subtract the difference from your units reading to know true RH.
In a nutshell here's how I do a salt test:
Milk cap or any small cap/container filled with salt; add drops of water until saturated. I pour off any standing water.
Put cap and hygrometer into a sealed container. I use quart sized zip seal bags and allow for small pillow of air. Voila! A saturated salt environment.
Wait...then wait some more...I calibrated yesterday and after 6 hours the RH reading was finally steady as it didn't change hour 7 and called it.
Subtract your reading from 75 and write that number down on masking tape and stick it to your incubator as reminder.
Ex: your reading is 85%, 75-85= -10, you'll always subtract 10 from your units reading for true RH. My unit yesterday was 8% off and have read of peoples devices being off as much as 15%. It makes a big difference if your 15% low at hatch time (chicks will dry and stick to shell and unable to zip) or can't figure out why the air cells are not growing or growing too large.
Note: battery powered hygrometers will vary a lot depending how new or drained the battery is. Always perform a salt test start of every hatch season and if the battery is changed.
For instance by unit last year was off 2% and with same battery in was off 8% yesterday and today the battery died so am performing a new test as it has a new battery.
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